In the realm of computers, the term PC has taken on two meanings. But they have exclusive definitions when they are related.
Originally, the term PC stands for a personal computer. It means a computer can be considered as a PC or a personal computer when it comes to using it personally by a person. The computers used in the home or offices are considered personal computers. As Mac is designed for personal use; hence, on the basis of this definition, a Mac computer is considered as a PC.
However, the term PC became something more specific when the first computer, model number 5150, was introduced by IBM in August 1981. Since when the PC occupied the place of IBM-compatible computers. In modern times, if anyone talks about the PC in terms of computer, it is commonly referring to an IBM-compatible computer. So, a Mac computer is not IBM-compatible; hence, it is not considered a PC.
Although in most cases, the term PC is referring to IBM-compatible computers, it is still a short form for the personal computer. A Mac doesn’t run Microsoft Windows. Hence, in a specific sense, it is not a PC.